Sec 7: Double-Angle Functions

Question 1

Cos 2u = ?

Answer 1

Cos^2 u - sin^2u = 2 cos^2 u - 1 = 1 - 2 sin^2 u

Question 2

Tan 2u = ?

Answer 2

1 - tan^2 u

Question 3

Sin 2u = ?

Answer 3

2 sin u cos u